Beating heart surgery via right thoracotomy for reoperative mitral valve surgery: a safe and effective operative alternative.

OBJECTIVE: Right thoracotomy using ventricular fibrillation with cooling has been used for redo mitral valve surgery. This approach avoids the complications of redo sternotomy, such as injury to prior grafts and hemorrhage. As a further refinement, we have used a beating heart technique to further minimize complications while simplifying the operation.
METHODS: We reviewed the outcomes of 450 patients who underwent redo mitral valve surgery via a right thoracotomy from 1996 to 2011 at the University of Michigan. Of these, 134 patients underwent redo mitral valve surgery with ventricular fibrillation, and 316 patients underwent beating heart surgery. Although operative eras were consecutive, patients' age, risk factors, New York Heart Association, and preoperative left ventricular ejection fraction were not significantly different. Core temperature on cardiopulmonary bypass for beating heart surgery was 32°C versus 26°C for ventricular fibrillation.
RESULTS: Patients undergoing beating heart surgery had shorter periods of cardiopulmonary bypass: 81±9 minutes versus 113±36 minutes. Beating heart surgery required less blood products than ventricular fibrillation: 1.65±2 units versus 3.8±5 units packed red blood cells, 0.6±1.2 units versus 1.8±4 units fresh-frozen plasma, and 1.02±4 versus 7.5±17 platelet packs (all P<.01). Conversely, patients receiving ventricular fibrillation required longer postoperative ventilation: 34±101 hours versus 15.5±27 hours (P<.01). The 30-day mortality was similar for both (6.5% for beating heart and 7.4% for ventricular fibrillation), and postoperative length of stay was the same at 7 days. Stroke rate was 2.6% for patients undergoing beating heart surgery and 3% for patients receiving ventricular fibrillation. Significant operative complications were uncommon; there was no catastrophic hemorrhage, and only 2 patients receiving ventricular fibrillation and 2 patients undergoing beating heart surgery required reexploration.
CONCLUSIONS: As reoperative cardiac surgery continues to increase, techniques that safely facilitate operation while improving outcome should be adopted. As an operative alternative, redo right thoracotomy mitral valve surgery on the beating heart is associated with shorter bypass time, less transfusion requirements, shorter postoperative ventilation, and lower mortality. This safe and effective approach should be considered for this complex operation.